Clarifying space use concepts in ecology: Range vs. occurrence distributions.

Area of Science:

• Ecology
• Conservation Biology
• Movement Ecology

Background:

• Quantifying animal movements is crucial for ecological and conservation research.
• Numerous methods for estimating animal home ranges have been developed over the past 50 years.
• These methods broadly fall into two categories: range and occurrence distribution estimators.

Purpose of the Study:

• To demonstrate the importance of correctly distinguishing between range and occurrence distribution estimators in animal movement analysis.
• To highlight the potential negative consequences of conflating these two types of distributions for ecological inference and conservation.
• To provide guidance on the appropriate use of each estimator type.

Main Methods:

• Theoretical analysis of movement ecology concepts.
• Computer simulations to test estimator performance.
• Empirical analysis using real animal movement data.

Main Results:

• Conflating range and occurrence distributions can lead to significant errors in ecological studies.
• Estimators of occurrence distributions often result in home ranges that are smaller than actual use areas.
• Improved tracking technology exacerbates the underestimation problem when using occurrence distribution estimators for home ranges.

Conclusions:

• Home range estimation requires the use of range distribution estimators (e.g., kernel density estimation).
• Occurrence distribution estimators (e.g., Brownian bridge movement models) are suitable for other movement questions like path crossing or location visits.
• Appropriate selection of estimators is vital for accurate ecological inference and effective conservation strategies.